I've seen one build which stacks IAS/int/vit instead of int/CC/CD. Instead of mana-heavy skills it uses poison dart/fire bomb as main attack. That allows for PtV to be used! Stacking
Int really high also scales great with gruesome feast.
It is probably cheaper since it strays away from the very popular cc and cd.

and as a side note, I don't think IAS is good for zombie bears, too much mana drain. I think int/crit chance/crit dmg are better choices for zombie bears. IAS works great for darts/firebomb because they don't cost any mana to cast hardly

I know that bears are hella expensive mana wise, but you would kill the elite on mp2/3 in few seconds anyway, so I would say it really does not matter anyway, for higher MPs, yea, that might be a problem, but I am not aiming for that.

Firebomb + bears is a good synergy.
Basic concept is: aoe cheap trash killer - firebomb, save mana for bear burst against elite, dump mana with bears vs elite.
Alternative of this is for example acid rain build as spender, and use darts vs elite (low mana cost). Second combo is weaker against elites, but kills trash faster, as acid rain is more powerful than firebomb.

What is important to use mana efficiently. Mana = damage. If you run all the time with firebomb, each time your mana is full (saved to use bears vs elites), you "waste damage". Build that uses acid rain as main skill constantly use mana pool, and them when oom use cheap skill to finish elites. But usually kills them much slower, since no cheap mana skill can match bears (not just cheap skill but any actually..).

Ideal combo would be to have enough mana regen to use acid rain vs trash, and bears vs elites, but this is difficult to achieve,

Okay, thanks. I have another question, is it better to keep zuni boots even with fire bomb, does the +8% dmg help fire bomb too or does it only add to the bears since its poison? I am kinda confused by that.